(1) Field of the Invention
The present invention relates to the field of making knit articles, and, more particularly, to preventing the raveling of an edge portion of a knit article such as a knit glove.
(2) Description of the Prior Art
Knitting processes have been used to make a variety of products and garments for quite some time. This textile fabrication technique creates comfortable items that are pliable, have high extensibility and that are relatively inexpensive. Generally, knitting provides productivity and lead time advantages compared to weaving processes. Knitting machinery is better adapted to producing small lots of goods and provides a shorter lead time and quicker response to such orders. In many respects knitting processes are faster than wovens and offer the benefits of providing body sizes and full-fashioned garments. Other knitting advantages include the low initial capital costs, the lack of a need for expensive yarn preparation, the small area of floor space required for the equipment and the need for fewer auxiliary machines during operation. Knitting processes have been carried out in the textile art with a wide range of natural and synthetic yarns.
Despite all these advantages, a knit garment or article, and in particular a knit glove, suffers from a drawback. Knit products are susceptible to raveling. Raveling is defined technically as the process of undoing or separating the knit of a fabric. The term also refers to the process of removing yarns consecutively from a fabric and, further, to a loose yarn that has been partially or wholly detached from a cloth. As a practical matter, it is known that a loose end extending from a knit product may be pulled and, under the right circumstances, an entire knit item may be pulled apart simply by pulling on the loose end.
For glove makers, this problem has been particularly troublesome. One approach for dealing with the problem involves an extra sewing step. After knitting, the edge portions of knit glove cuffs are sewn manually on serging machines to apply an overlock stitch designed to hold any loose ends of material in place. This overcast sewing typically is accomplished with a polyester, nylon or cotton yarn. It will be readily appreciated that the additional serging step is labor intensive and can add significantly to the manufacturing cost of the glove.
Another approach for addressing this problem involves the use of a fusible adhesive yarn of the type disclosed in U.S. Pat. No. 5,572,860 to Mitsumoto, et al. In the Mitsumoto yarn a spun core yarn having an elastic component and a heat fusible multi filament yarn strand are twisted with each other in the same or opposite twisting directions. The spun core yarn is itself composed of an elastic yarn and a non-elastic short fiber assembly spun together in the direction of the elastic yarn. The non-elastic short fiber assembly encloses the circumference of the elastic yarn as a core. The non-elastic short fiber assembly is expanded and bent by the contraction of the elastic yarn. The fusible adhesive yarn is either introduced in the spinning operation or wrapped around the spun core. As a result the low melt attached to the short fibers upon thermal setting, the adhesive yarn is solidified into small blocks located in a form of dots such that the expanded short fibers cover the small blocks of solidified fusible adhesive yarn.
In commercial applications it is believed that the yarn described in the Mitsumoto, et al. patent typically has been produced using the combination of spandex, polyester and a low melt yarn. This combination produced favorable results with respect to eliminating the additional labor associated with the sewn-in yarn described above. Nevertheless, this yarn has a unique set of drawbacks. First, the need for three components in the yarn makes it a relatively high cost solution. The tension in the elastic component of the spun core yarn must be carefully controlled so as to produce just the right amount of expansion and opening of the short fiber assembly. The spandex component is provided with a silicone finish, which, even in minute quantities, can contaminate particular types of work areas. For example, controlled environment chambers used for automobile painting are particularly sensitive to silicone contamination arising from the spandex finish. Lastly, experience with fusible adhesive yarns of this type has shown that, after repeated washings, the internal bond created by the fusible yarn breaks down.
Another type of commercially available heat fusible yarn is comprised of an elastic core strand, one or more wrap strands of a non-elastic material such as textured polyester and a cover strand comprised of a heat fusible yarn. The heat fusible yarn is placed on the outside of the composite yarn structure so as to be in intimate contact with and more readily bond to adjacent yarn strands. A typical heat fusible yarn of this type is available from Supreme Corporation as style number 343. This yarn provides acceptable results but does require a two-step manufacturing process given the separate wrapping steps needed.
There are other considerations for including a heat fusible yarn in the edge portion of a knit article subject to raveling. The yarn employed for this purpose must have sufficient fiber structure cohesiveness to knit properly in automated knitting equipment. That is, if a multifilament yarn is used, the individual filament strands should not flare or be too loose for proper knitting equipment performance. For this reason, it may not be desirable to feed the fusible yarn alone into the last several courses of the edge portion of the item being knit.
It has been found that knitting the low melt fusible yarn side by side with another yarn does not address these problems. The exposure of the low melt fusible fibers to adjacent fibers in the yarn structure may be inconsistent leading to uneven bonding and unsatisfactory ravel prevention performance.
Lastly, it has been found that problems may be encountered with the cutting operation that separates the glove from the knitting machine at the end of the glove knitting cycle. The machine integrated cutting mechanism may not function properly if a very open yarn is used in the last several courses of the glove.
It follows that there is a need for a knit article incorporating a heat fusible composite yarn so as to address the raveling problems in the edge portion of knit products. The article and yarn should use readily available, low-cost components and manufacturing techniques and should be capable of being heat treated using existing equipment to prevent raveling of the edge portion of the article.